常常听到木工老师傅讲“直木顶(抵)千斤”。意思是说直立的木料可以承受很大的荷重。这句话有它一定的科学道理,但也不能一慨而论,其实,直立的木料并不是都能承受很大的荷重的。我们不妨先做一个试验,用同一材料做两根木杆,它们的截面形状和尺寸均相同,但长度不同(见右图)。 I often hear the woodworking master talking about “straight wood (arrived) jacks”. This means that standing wood can withstand heavy loads. This sentence has its scientific certain truth, but it cannot be said generously. In fact, the upright wood cannot bear a heavy load. We may wish to do a trial first and use the same material to make two wooden poles that have the same cross-sectional shapes and dimensions but different lengths (see the figure to the right).